The Blocking Removal Of Sulfate Scale And Scale Removing/inhibiting Technology Study

Water injection is one of the important ways to develop low-permeability oilfield.The main water source of Jiyuan Oilfield water injection is the underground Cretaceous Luohe layer water,and the Luohe layer is rich in SO42-(1200mg/L~2900mg/L),The high concentration of Ba2+ and Sr2+(700mg/L~5000mg/L)in the water resulted in the formation of insoluble barium strontium sulfate scale,which caused the increase of pressure of the injection well and the lesser formation;besides the wellbore and the ground gathering transportation system also had barium sulfate scale of the serious phenomenon,resulting in ground pipe network congestion,oil recovery and other series of problems,which can lead to significant impact on stable production.This article through research,in-depth understanding current situation of the ground system,wellbore and stratigraphic scale.Using a large number of experiments including X-ray scale analysis,water quality compatibility analysis,scaling prediction and scaling factors analysis to illuminate the scaling mechanisms of Jiyuan Oilfield.The results show that the TH-60 scale inhibitor is selected for the wellbore and the ground gathering and transportation system;A New type of formation plugging agent YHJD-1 were used to block the barium strontium sulfate scale formed by the formation which used the slow sulfate cleaning technology.According to the scaling characteristics of Jiyuan Oilfield,the TH-60-based scale inhibitor and YHJD-1-based formation plugging agent were used in the field combined with the concept of eliminate and defense,which used the dripping chemicals technology,oil casing annulus dosing,formation squeeze process,not only effectively restrain the scaling tendency of wellhole and ground system,but also the effect of dissolving of the sulfate scale were obviously,basicly achieve the purpose of prevention and control.